1. The Field of the Invention
The present invention relates to optical modules for use in optical devices. More particularly, embodiments of the invention relate to optical receiver modules, optical transmitter modules, and optical transceiver modules for use with a host system.
2. Related Technology
A typical optical transceiver is a device that includes both a receiving optical subassembly (“ROSA”) and a transmitting optical subassembly (“TOSA”). The ROSA receives a light signal with a photodiode or other light detector, which converts the light signal into an electrical signal. The electrical signal is then amplified and further processed for use by the receiving device. The TOSA typically includes a laser that generates light that is launched into the optical network. When a device desires to transmit data, the light emitted by the laser is modulated accordingly. Thus, the data carried by the light signal often originates as an electrical signal and the conversion of an electrical signal into a light signal is usually accomplished using the laser in the TOSA.
A typical transceiver includes a TOSA, a ROSA, and a printed circuit board that includes a microcontroller, a laser driver, and a post-amplifier. Each component of a typical transceiver adds cost and complexity to the manufacture of the transceiver. For certain optical devices, one or more components in a transceiver go unused, or are redundant, and are therefore unnecessary.
One example of an optical device where certain components of a typical transceiver go unused is an optical network test access point (“TAP”) device. In general, a TAP device is a device that includes various connections by way of which a user can gain access to a network data stream for the purpose of performing monitoring and testing evolutions. Other devices can interface with the TAP device so as to monitor connections of the network in which the TAP device is employed.
A significant problem with a typical TAP device relates to the transceivers and ports by way of which the TAP device receives and sends optical data. In particular, a typical TAP device includes one transceiver connected to each port. In other words, a typical TAP device has one ROSA for each TOSA. However, a typical TAP device can require more ROSAs than TOSAs for a given application. Therefore, some of the TOSAs associated with the transceivers that are integrated into the TAP device are not fully utilized.
That is, for a transceiver connected to an input port of a TAP device, for example, only the receiver side of that transceiver that may be utilized where the port is input-only, and the transmitter side of that transceiver will necessarily be idle. Similarly, for a transceiver connected to an output port of a TAP device, only the transmitter side of that transceiver that may be utilized where the port is output-only, and the receiver side of that transceiver will necessarily be idle. Consequently, the purchaser of such a TAP device is compelled to pay for unused components and unused functionality.
Another problem with a typical TAP device is redundancy of components resulting in increased cost. In order for an optical component such as a ROSA or a TOSA to function properly, certain components (e.g., microprocessor, laser driver, post amplifier) are needed. Thus, each transceiver in a conventional TAP device includes a printed circuit board on which are mounted the necessary components. In other words, the components needed to operate the ROSAs and TOSAs are duplicated in each transceiver. The duplication of components adds cost and complexity to the TAP device.